On screen, Dakota Fanning seems to be one of those eerily wise-beyond-her-years child actors, a porcelain doll exterior concealing a mature, poised adult. But when the 10-year-old actress comes bounding into a hotel room at the Four Seasons Hotel in Beverly Hills, there is no doubt that Fanning is a real live little girl.

”I want a dog REALLY REALLY bad,” she moans, tucking her feet underneath her and bouncing up and down in her chair. ”But my mom’s really clean, and she thinks dogs are dirty, so I don’t know if I’m going to get one anytime soon.” Just thinking of a dogless future, her smile, which is missing more than a few baby teeth, fades into an expression of aching disappointment. God save the parents who have to say no to this heartbreaking little face.

But really, what kid needs a pooch when she can breezily chat about playing Ping-Pong with Denzel or double solitaire with ”Man on Fire” costar Marc Anthony on the set? Fanning even talks about Robert De Niro, with whom she costars in next year’s supernatural thriller ”Hide and Seek,” as if the legendary actor were just a nifty playmate. ”I got to go to his country house and meet his kids, so he couldn’t have been any nicer to me,” she shrugs.

As much as Fanning is a normal little girl who just happens to have A-list friends, her job has clearly exposed her to an adult world. On the set of ”Man on Fire,” she had a personal bodyguard at all times, a necessary precaution after several crew members were held at gunpoint and one was carjacked. ”I didn’t really worry about it. The bodyguards were very nice.”

But the off-set action paled in comparison to the violence on screen. Washington’s ruthless character lops off the fingers of an enemy, shoots countless bad guys, and actually turns one man into a human bomb. Fanning, who’s seen the R-rated film, dismisses the gore. ”After I was done with any scary scenes, it was fun, because I knew what goes into making the fingers cut off. It’s all pretend,” she explains.

Off the set, the pint-size actor still enjoys make-believe, albeit a less gruesome version. ”Me and my sister [5-year-old Elle, also an actor] pretend that we’re at Hogwarts. But I have to pretend that I’m Harry Potter’s sister, because I don’t really want to be Hermione. I don’t look like her, so I have to make up a character.”

Preferably a character with a dog. At the mention of puppies, Fanning springs up in her seat again, eyes wide with excitement. ”I already have a leash picked out, and it has feathers around the collar! I can’t wait! I’m so excited! I’m gonna call her London, like England. And I’m gonna paint her toenails!” Well, maybe some things really are better left to the imagination.